Audio-only(Prerecorded):Same as Level A.
Audio-only(Live):Same as Level A.
Video-only(Prerecorded):Same as Level A.
Video-only(Live):Same as Level A.
Synchronized media(Prerecorded):At level A, speech commentary is not mandatory, but level AA obligates audio description(1-2-5a).
Synchronized media(Live):Provide caption(1-2-4b).